arch/x86/sgx.rst

1 .. SPDX-License-Identifier: GPL-2.0
4 Software Guard eXtensions (SGX)
10 Software Guard eXtensions (SGX) hardware enables for user space applications
13 * Privileged (ring-0) ENCLS functions orchestrate the construction of the
15 * Unprivileged (ring-3) ENCLU functions allow an application to enter and
38 with an enclave. It is contained in a BIOS-reserved region of physical memory.
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67 ----------------------
76 remain read-only.  EPCM permissions may only impose additional restrictions on
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97 .. kernel-doc:: arch/x86/kernel/cpu/sgx/ioctl.c
104 --------------------------
113 .. kernel-doc:: arch/x86/kernel/cpu/sgx/ioctl.c
119 ------------
121 Entering an enclave can only be done through SGX-specific EENTER and ERESUME
122 functions, and is a non-trivial process.  Because of the complexity of
131 Instead of the traditional signal mechanism to handle these exceptions, SGX
132 can leverage special exception fixup provided by the vDSO.  The kernel-provided
133 vDSO function wraps low-level transitions to/from the enclave like EENTER and
135 a signal and return the fault information directly to its caller.  This avoids
136 the need to juggle signal handlers.
138 .. kernel-doc:: arch/x86/include/uapi/asm/sgx.h
147 ----------------
153 reinitializes all enclave pages so that they can be allocated and re-used.
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174 EINIT function takes an RSA-3072 signature of the enclave measurement.  The function
192 encrypt pages leaving the CPU caches. MEE uses a n-ary Merkle tree with root in
194 anti-replay protection but does not scale to large memory sizes because the time
199 MEE. TME-based SGX implementations do not have an integrity Merkle tree, which
200 means integrity and replay-attacks are not mitigated.  B, it includes
211 --------------
216 the enclave through special SGX instructions. A run-time within the enclave is
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224 configured with a library OS and run-time which permits the application to run.
225 The enclave run-time and library OS work together to execute the application
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238 This is effectively a kernel use-after-free of an EPC page, and due